Epidemiological data strongly suggest the involvement of an infectious agent distinct from HIV in the causation of K.S. The frequent occurrence of endemic and epidemic K.S. in both adults and children in Uganda and the collaboration between the Division of Infectious Diseases at CWRU and the Uganda Cancer Institute afford a unique opportunity to study the etiology of K.S. in depth. From a collaboration between this laboratory and the laboratory of Dr. Edward Mbidde of the Uganda Cancer Institute, we will obtain various endemic and epidemic K.S. tumor samples and patient sera for comparative studies. The K.S. patient tissues and sera will be used to test the hypothesis that a highly cell associated virus may be responsible for the various forms K.S. Specifically, we seek to Specific Aim 1: Establish in vitro culture of lymphocytes and tumor cells from epidemic and endemic K.S. patients. Specific Aim 2: Characterize the epidemic and endemic K.S. tumor cells in culture.